Today, in various common devices, a button structure is often used to trigger switches of a device to activate relevant functions of the device. The various switches have respective maximum bearable forces; that is, when a pressing force applied by a user is greater than the maximum bearable force of a switch, the switch may be destroyed. Accordingly, how to effectively prevent a switch from being destroyed due to an excessive force is an issue that manufacturers have to deal with. Therefore, after an extensive research in conjunction with theoretical knowledge, the inventors provide this invention that is reasonably designed and effectively solves the above problem.